Is there any way to determine what part of the model year a given block was made? I have the casting number but that gives only the year.

The engine block ID numbers, stamped into a pad at the front or rear of the deck depending on the year the engine was made, will tell you when that particular block was made.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

OK, found that. The marks are very shallow, so it was difficult to see. Thanks.

The numbers on two blocks as rather different.

BT 225 12 09 2
T 22 3 07

I can see absolutely no mark aat all before the T on the second block.

Where can I find material that will convert the numbers for me?The numbers themselves don't show up by Google.

That one's kind of interesting. B 225 12 09 2 would indicate a 1966-model 225 engine made on December 9, 1965 (the trailing "2" indicates 2nd shift at the production plant). But you've got a "T" after your "B", which doesn't parse. Are you sure that first "B" isn't actually something else, like maybe an 8? Because 8T 225 12 09 2 would indicate a 1978-model 225 built at Trenton Engine Plant on December 9, 1977, second shift. How many freeze plugs do you see on the manifold side of this engine? If five, it's definitely not a 1966 engine. What's the casting number of this engine? A 1978-model engine would be a cast-crank item and we'd be able to solve the mystery by looking at that.
That one's a 1963-model 225 made on March 7, 1963.

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Too many people who were born on third base actually believe they've hit a triple.

Thats very clearly a BT in front of the 225 12 09 2. This one came in the 1965 Valiant 100.

The casting number on both of these blocks is 2463430. Both have 3 freeze plugs

Very interesting. The "BT225" block would not be original to the '65 you took it out of; it's a '66 engine as indicated by the combination of casting number 2463430 together with the "B" in the engine ID number.

The most likely explanation is that Trenton Engine Plant either switched or experimented with a nonstandard-for-'66 engine numbering system, without that information making it into the '66 master FPC.

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Too many people who were born on third base actually believe they've hit a triple.

And THAT is very interesting. I've had this car since it had 19,000 miles on it, both according to the odometer and according to the owner's maintenance records. It had been parked in a garage for many, many years since the owner had a stroke. When I bought it in 1987 it looked like it was a week out of the show room.

The guy had put new tires on it just before he quit driving. The little tits sticking out of a new tire were still hardly touched. But being parked so long they went totally bald in a 1200 mile trip! (Other rubber parts dusted out as well)
If that engine's a '66 I can't imagine how it got into the '65, all things considered. Hm. I'll have to check how a '66 car was different from a '65. Maybe the paperwork on the car is wrong.

There is, of course, a theoretical possibility that the engine had to be replaced shortly into it's life. That would be a very unusual story. One that doesn't appear in the first owner's very meticulous maintenance book. Strange.

Is there any place where a guy can look up old VIN's? I tried a dozen last night and they all went back only to 1981.

7N53H119762

That's not entirely out of the question. Engine warranty work early in the car's life (conceivably very early, i.e., before the buyer bought it but after the '66 models were in production) could explain a low-miles car with a later-than-the-car's-year engine.
That's another distinct possibility.
For US-built cars:

1965 VINs are 10 digits long and should be all numbers. Please re-check yours; it'll be on a metal plate at the forward driver's doorframe.

1966 VINs are different; a 1966 Valiant would start out VL41B6 (1966 Valiant V100 4-door, 225 engine), VL21A6 (1966 Valiant V100 2-door, 170 engine), VH23B6 (1966 Valiant V200 2-door hardtop, 225 engine), etc.

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Too many people who were born on third base actually believe they've hit a triple.

Right you are. I spent about an hour going over this. The VIN is:

1157289994

There is something very strange about the car's history. As I said, the odometer and owners records indicated 19,000 miles. In addition, the dealer inspection certification card on the glove box door goes only to 18,000. All consistent. That card says the car was sold 9/65, possibly explaining the '66 engine.

But I found some "hen scratches" in the owner's manual I hadn't seen before showing mileage up to 63,000. The 19,000 I saw when I got it simply could not have been 119,000. It was far too clean at that point.

A Ford dealership got involved at one point. Maybe they didn't want to work on it and put in a new engine? And reset the odometer?

Perhaps they told my guy they got it from a little old lady who only drove it 500 miles. His first maintenance entry was at 2000.
Even if the engine were original, something has to explain why it dropped to where my guy seemed to think he was buying a new or very nearly new car.

Maybe I should get in touch with Scotland Yard.

Car is a 1965 Valiant V100, 6-cylinder engine, built at St. Louis, serial number 289994. No way to tell from the VIN whether it originally came with a 170 or a 225. I'm going to run your oddball engine number past a Mopar-numbers-expert friend of mine (no, not the self-proclaimed "guru") and see what he says about it.

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Too many people who were born on third base actually believe they've hit a triple.

I have the engine half apart now, working on that rear cam bearing. Would there be any particular advantage to switching from the '63 block to the '66 block?

There is no difference between a '63 and a '66 225. Pick the components in the best condition.

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Too many people who were born on third base actually believe they've hit a triple.

Thank you.

BT 225 12 09 2


B - 1966 model year
T - Truck engine
12 09 - Date of assembly - December 09, (1965)
2 - 2nd shift

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Bill
Vancouver, BC

T for truck is an interesting possibility, but none of my '66 factory info (US or Canadian) indicates that T was used for that designation. It's entirely possible you've got documentation I haven't got; where's your info comin' from?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.